Sahih al-Bukhari 475
صحيح البخاري#475SahihNarrated `Abbad bin Tamim:that his uncle said, "I saw Allah's Messenger (ﷺ) lying flat (on his back) in the mosque with one leg on the other." Narrated Sa`id bin Al-Musaiyab that `Umar and `Uthman used to do the same
Scholarly Authentication
We show the most cautious grade (weakest-wins) as the overall label. Individual scholars graded it as follows:
Every narration in Sahih al-Bukhari is accepted as Sahih (authentic) by the established status of the book.
In-book reference: 8:123